Electric railway drive



2 Sheets-Sheet 1 Filed Aug. 15, 1927 Feb. 25, 1930. F. PRANTL ELECTRIC RAILWAY DRIVE 2 Sheets-Sheet 2 Filed Aug. 13. 1927 IIlllllllllllllllllllllllllllllllllllllhllwlllllllll li'atel zeit Febo 25, 1936 arms memos, es wsmiiicmi, cm, @i seem",

SWITZERLAND, ASEEIGETOE, TQ A. BRQWN EQVEJR-I SWITZEEZIeAND, A JGINT-ETOQK CGTEPANY 0F EWITZERLAND ELEC'ERZG RAILWiY IDEZTVE Applicsttoo et it, 1953?, Sexist its. moses, amt in Germany August 3.8,

invention reiotes to eiectric railway 123 perticiiiec relation to drives iocomotives one: like vehicles, utilising combi ceci eciiiesion and rock drives, although iii some aspects the invention is not iimiteci thereto,

in. ceicteiic types of ieoziotives of the foregoiiig character toe vehicie is driven by in= ductioii motors Wound. to operate on two clifi eient poie The motors are operated with a low poi e number on the level stretches of and with s large pole number L s retches of the rose}. @n account mount of energy requireii to i-oc motives 01 trains in descending; es the trains are biekeoi eiec on by operating the o generators returning encountered in the op liver; dives to monoa i 1 1 N d W coco to sign. at Llell es erect supply WO'lllCi 1 contain. in such the tram would be descend be on, Cii'ifiC'ilitZGFJ of overcome by pro- :ive strongest to perat iow descending going the presence of the f e troiiey time teecimg the vehicie To this the induction motor has one oi? its Wiiiofiogs to be excited; item en excites operated by the descemdiog; vehicle, for theseioy genereting cur rent in the coopeteti ig windings of the ethos memioec oi? the motor, seifi current being suppiieci to suitable braking resistors. The various windings oi the motor are so an ranged. as to secure nigh eiiieiency, 190th during iii iviog, es welt es issing; bee-king opei etiozos The foregoing, and other objects oi the i vstit ies i g description of exempiificetion thereof, reiice being}; had to the accompanying drawings wherein 1 is an eievstionei view of eiectiic locomotive embodying the invention.

Fig. 2 is a simplified circuit diagram 0; "h.

Eiectric iocomotives for mountei Ways utilizing an adhesion drive 01 i'fSijCilES onci a. drive 0' es, very often. icpioy (iii inflection tyne that ere arranges for A 4- L i 4 s m ieistion. ice ZQOLULS eie eioperate 'vvitii e large zinc e teiatlvei'y low speed 1 s trective effort, on the steep 'ooie numbei, 0 as to give s high giacies, wine crating); on the cock cirive, the speeo 7 between 8 enci i i kiiometers per hour. operation on the ievei Witt adhesion e speed oilti to 30 iZiiOlDEtfiiS GPGPEL'iZiEZg the motors with e sme oeie to loumbeiz in the usiiei contructi es, 'tiieinotovs ere obi-ranged with poiemumbe i'etic l to 2. in the practice-ii opeietioii so rsiiways, iifiicoities have oeeii ex'oe because of'tiie usual iergze breaking efoe has to be disposed of during the V the locomotive 01 train.

j'ti'i oescent "Uiic'iei ordiiiery coii- (iitions, regenerative biz-king is relied upon, the motors being connected for larger pole number eiici operating" es asynchronous so generators, thereby returning energy to the line.

However, in the mountainous regions Where such railways operate, the relatively isoieteci supply lines often become defective and the supply line may remain Without voltage for e considerable period; 01" time. such cases the train may be stisndeei on s high isoieteci portion of the track, it being; imoossib' e to descend because the chee es o1.

braking the locomotive andtheimpossibility of regenerative braking in the absence of voltend small pole number rotor induced by a flux age on the line.

According to the invention, the foregoing difiiculties with prior-art induction motor drives of such locomotives are avoided by arranging the rotor or secondary winding of the motor so than when operating with a large number of poles, it is possible to brake the locomotive electro-dynamically independent of the voltage in the supply line or trolley wire. In the preferred arrangement, the secwinding is constructed in the form oi a squirrel-cage winding having relatively ation with the small pole number and having special connections for providing a relatively high resistance current path for currents o'f'the higher pole number. In this way it is possibleto utilize, to a certain extent, the small pole number winding to exercise auxiliary braking action at the low pole number operation.

Referring to the drawings, a locomotive 1 intended to be operated over level and graded road sections, is provided with wheels stator, winding 12 2 cooperating with rails 3 for driving said locomotive by adhesion and with a gear 4 cooperating with a rack 5 for propelling the locomotive over the steep grades of the road. The wheels and gear are arranged to be driven from a motor 7 through suitable intermediary driving mechanisms, as for instance, pinion and drive rod 9. Ordinarily, the rack will extend only over the steep sections of the road on which the rack drive is to be utilized.

In the preferred arrangement of the locomotive, the driving force is obtained from one or more motors of the induction type that are arranged to be connected with a polyphase supply line 10, shown in the form 0 trolley wlres.

A simplified diagram of the elements of the motor drive and the connections thereof is shown in Fig. 2 of the drawings. The induction motor 7 comprises a stator or primary member 11 cooperating with the concentric rotor or secondary member 6. The stator is provided with windings arranged to operate with a relatively large pole number at the low speeds when driving the locomotive on the grades, and with a small pole number at the relatively'hi 'h speeds whendriving the locomotive over the level portions of the road. This is indicated by the two distinct threephase star connected windings 12, 13 on the being designed for o eration with 2 P-poles, and winding 13 eing designed to operate with P-poles. The rotor or secondary member 6 of the induction motor has two distinct windings, a P- ole number winding 14 and a 2 P pole num er winding '15, for cooperation wit-hthe stator windings.

3 to 5 of the drawings. ber winding 15 is disposed in slots 16 of relalow resistance for oper-- aveaore the rotor armature is best shown in Figs.

The 2 P-pole numtively large width near the periphery of the armature core 17, while the low pole number winding 14: is disposed in relatively deep and narrow slots 19 farther away from the periphery of the armature. In the preferred arrangement as shown in the drawing, the wide slots for the larger pole number winding and the narrow, deep slots for the narrow pole number windings are combined and arranged one below the other. The large pole number winding 15 is of the wound type and is connected to three slip rings 20 arranged to cooperate with brushes 21 leading to a control rheostat 22. The low pole number winding 14 is of the squirrel-cage type and comprises winding loops having a ole itch twice the size of the polt pitch 0 the arge pole number winding, the loops being short circuited on one side by a short-circuitingring 24.

In order to permit utilization of the squirrel-cage winding when operating with the larger pole number, particularly during braking, the loop heads 25 on the side opposite. the short circuiting ring 24 have taps to which are connected resistors 26 that are in turn short circuited by a second short circuiting ring 27. The individual loops of squirrel-cage winding are so arranged that,

8 when the rotor operates with the 2 P-pole number field, the s'uirrel-cage winding 14: will operate as a w nding, circulating currents induced by said 2 P-pole number field through the resistors 26 and the short circuiting rings 24 and 27. Accordingly, the winding wi I operate both on the low and the lange polenumber.

locomotive provided with a motor of the type described above ma be electro-dynamically braked in descent rom a grade by the connecting the motors for the 2-pole number operation and permitting the descending locomotive to chronous speed so as to return energy to the supply line 10. A Full brakingaction may also be secured in case of the failure of the line voltage, when asynchronous regenerative action is impossible, by connecting the stator winding 12, through a switch 31 to an auxiliary exciter 32 that may be driven by one of the locomotive axles. The rotation of the secondary motor-member 6 within the field induced by the currents from the exciter 32 will generate in the windings 14 and also in windin s 15, currents that will electro-dynamical ly brake the locomotive. It will thus be possible to descend from the grade independently of the conditions of the supply line and without necessitating the provision oi expensive mechanical braking equipment as would otherwise'be required.

For the satisfactory operation of drives of drive the rotor 6 at super-synthe scope oi the see ers the foregoing character, it is important that the secondary winding 15 of the larger pole number that is principally active during the braking period shall be referred in the design over the low pole humher Winding and it is for this reason that the large pole number Winding is placed near the periphery so as to have low leakage. Since the braking current that the Winding is required to carry may be very lerge, the mounting near the periphery will also help in dissipating the heat losses in said Winding,

The employment of induction motors of the type described above greatly improves the operation oi rock locomotives of the above described character and real-res the some more independent of breakdowns and temporary interruptions in the supply when descending grades their in prior art drives known heretofore Many modifications oi the in. veution as described above will suggest themselves to those skilled in the art and it is accordingly desired that the appended claims be given. a construction commensurate with invention,

1 claim:

1., in an electrically prorielled vehicle, a driving motor or the induction type comprising aprimery member, a secondary member, Winding connections on said primary member for operation with relatively large pole number at low speed and with a relatively low pole number at hi h speeds, esli ring Winding on said secon member for operation on the large pole number, and a Winding consistiri of short-circuiting loop coils on said secon sry member for operation with said low pole number, said secondary large pole number Winding having relatively less leakage reactence than said low pole number Winding.

2. in an electrically propelled locomotive, a driving motor of the induction type comprising a. primary member and a secondery merriber, winding connections on said primary member for operating the some either a ler e ole number or with a small pole number, sold secondary member comprising an or mature heviiiga set of relatively wide slots near the periphery of the armature end set of relatively deeper slots, :1 large pole number secondary Winding disposed in the relatively Wide slots for cooperating with the large pole number winding connections or said primary member, a small pole number winding iii said deep slots for cooperating with said smell pole number Winding connections of said primary member,

3. in en electrically propelled locomotive, a driving motor of the induction type comprising a primary member and a secondary member, Winding connections on said primary member for operating the sonic eitherwith a large pole number or with a small pole number, seid seconderyinember comprising an erraeture having s set of relatively Wide slots near the peri hery oi the armature arid a set of relatively deeper slots, a large pole number secondary/winding disposed in the relatively Wide slots for cooperating with the lei-go pole number Winding connections of said primary member, and a small pole number Winding said deep slots for cooperating with said smell pole number Winding connections of said primery member, said secondary large pole nuiir her winding being of the slip-ring type, and said secondary small ole Winding consisting of short-circuiting loop coils.

4;. in an electrically propelled locomotive, e driving motor oil the induction tygoe .compris ing s primary member and a secondary member, winding connections on said primary member for operating the some either with at large pole number or with at small pole numher, said secondary member comprising an armature having a set of relatively Wide slots near the periohery of the armature a set of relatively eeper slots, a large pole number secondary Winding disposed in the reletively Wide slots for cooperating "with. the large pole number Winding corrections oi? said primary member, and e smell pole number winding in said deep slots for cooperetiiig with said small pole number Winding connections of said primary member, said secondary lerge pole number Win-ding b ing of the sliprririg type, end said secondery small pole number Winding being of the squirrel-cage type, means for operating said motor with either said low pole number windings or sold large pole number windings for driving end for regeneratively braking said locomotive under asynchronous operation, and means for independently exciting said primary large pole number Winding COR" nectioris to electro-dynemically broke ssid locomotive by inducing currents in said secondary large pole number windings in testimony rvliereoi. l have hereunto sub scribed my name this 1st day of July A. D. 192?, at Zurich, Switzerland.

FRANZ FRANTL its 

